Electronic expansion valve control circuit and control method thereof, photovoltaic air conditioner, and storage medium

Abstract

The application relates to an electronic expansion valve control circuit and a control method thereof, a photovoltaic air conditioner and a storage medium, wherein a first output end of a power supply in the circuit is connected with a first end of an energy storage module through a first resistor; the first end of the energy storage module is also connected with a first end of a control module and a normally closed end of a relay respectively; a common end of the relay is connected with the first end of the control module and an electronic expansion valve respectively; a second output end of the power supply is connected with the first end of the control module and the electronic expansion valve respectively; a third output end of the power supply is connected with a first end of a relay coil and a collector of an optocoupler respectively; an anode of the optocoupler is connected with a power-off detection pin of the control module; a second end of the energy storage module, the power supply, a second end of the relay coil, a cathode and an emitter of the optocoupler are grounded; and a control output end of the control module is connected with a control end of the electronic expansion valve. Thus, the emergency shutdown of the electronic expansion valve is realized when the power supply is powered off.

Description

Technical Field

[0001] This application relates to the field of intelligent equipment manufacturing, and in particular to an electronic expansion valve control circuit and its control method, a photovoltaic air conditioner, and a storage medium. Background Technology

[0002] If a power outage occurs suddenly during the operation of a photovoltaic air conditioner, the refrigerant will remain in the pipes, increasing the risk of refrigerant leakage. Furthermore, if the refrigerant remains in liquid form in the low-pressure pipes or near the compressor's suction port, there is a risk of "liquid slugging" when the photovoltaic air conditioner restarts, which can easily damage the compressor. Summary of the Invention

[0003] To address the aforementioned technical problems, this application provides an electronic expansion valve control circuit and its control method, a photovoltaic air conditioner, and a storage medium. The specific technical solution is as follows: In a first aspect, this application provides an electronic expansion valve control circuit for use in photovoltaic air conditioning. The electronic expansion valve control circuit includes: a power supply, a first resistor, an energy storage module, a relay, a second resistor, an optocoupler, and a control module. The first output terminal of the power supply is connected to the first terminal of the energy storage module via the first resistor. The first terminal of the energy storage module is also connected to the normally closed terminal of the relay. The common terminal of the relay is connected to the first terminal of the control module and the electronic expansion valve. The second output terminal of the power supply is connected to the first terminal of the control module and the electronic expansion valve. The third output terminal of the power supply is connected to the first terminal of the relay coil and the collector of the optocoupler. The anode of the optocoupler is connected to the power-off detection pin of the control module. The control output terminal of the control module is connected to the control terminal of the electronic expansion valve. The control module is used to detect whether the power supply is powered off based on the power-off detection pin, and closes the electronic expansion valve when the power supply is determined to be powered off.

[0004] In one implementation, the energy storage module includes at least one RC energy storage unit, each of which includes a set of capacitors and resistors connected in parallel.

[0005] In one implementation, the control includes a voltage sampling pin, and a first terminal of the energy storage module is also connected to the voltage sampling pin of the control module.

[0006] In one alternative implementation, a voltage divider filter module is further provided between the first end of the energy storage module and the current sampling pin of the control module.

[0007] Optionally, the voltage divider filter module includes a third resistor, a fourth resistor, a fifth resistor, and a filter capacitor; wherein, the first terminal of the energy storage module is connected to the first terminal of the third resistor, the second terminal of the third resistor is grounded through the fourth resistor, the second terminal of the third resistor is also connected to the first terminal of the fifth resistor, the fifth terminal of the fourth resistor is connected to the control module, and the second terminal of the fourth resistor is grounded through the filter capacitor.

[0008] In one implementation, there is at least one electronic expansion valve, and the control module includes a main control unit and at least one drive unit. Each drive unit corresponds to one electronic expansion valve, and the main control unit controls the corresponding electromagnetic expansion valve through each drive unit.

[0009] In one implementation, the power source includes a first transformer, a second transformer, and a third transformer. The first transformer, the second transformer, and the third transformer obtain electrical energy from the power grid and output it. The output terminal of the first transformer is the first output terminal, the output terminal of the second transformer is the second output terminal, and the output terminal of the third transformer is the third output terminal.

[0010] Secondly, this application provides a backup power switching method for closing an electronic expansion valve upon power failure. The method is applied to a control module in the circuit described in the first aspect. The method includes: acquiring the level change of a power failure detection pin and detecting whether the power supply is interrupted based on the level change; determining that the power supply is interrupted, and closing the electronic expansion valve under the power supply of the energy storage module.

[0011] In an alternative implementation, the method may further include: acquiring the sampled voltage value of the voltage sampling pin, and detecting whether the energy storage module is storing energy normally based on the sampled voltage value.

[0012] Optionally, determining that the power supply has failed and closing the electronic expansion valve while the energy storage module is supplying power includes: determining whether the power supply has failed and whether the energy storage module is storing energy normally, and closing the electronic expansion valve while the energy storage module is supplying power.

[0013] Thirdly, a photovoltaic air conditioner is also provided, including a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus; the memory is used to store computer programs; and the processor, when executing the program stored in the memory, implements the control method of the electronic expansion valve control circuit described in any of the second aspects above.

[0014] Fourthly, a storage medium is also provided, wherein the storage medium stores instructions that, when executed on a computer, cause the computer to execute the control method of the electronic expansion valve control circuit described in any of the second aspects above.

[0015] Fifthly, a computer program product containing instructions is also provided, which, when run on a computer, causes the computer to execute the control method of the electronic expansion valve control circuit described in any of the second aspects above.

[0016] Compared with the prior art, the above-mentioned technical solution provided in this application has the following advantages: During the normal power-on operation phase, the circuit provided in this application provides the following advantages: The first output terminal of the power supply is current-limited by the first resistor to stably charge and store energy for the energy storage module. The second and third output terminals continuously provide stable operating voltages for the control module, the electronic expansion valve drive circuit, and the relay coil. The optocoupler input terminal is energized and conducting, and the power failure detection pin remains at a low level. The control module determines that the power supply is normal based on this. When the main power supply suddenly fails, the second and third output terminals lose power. The diode on the second output side isolates the power supply port that is under voltage. The energy storage module immediately releases the stored energy to supply power to the control module and the electronic expansion valve. The optocoupler is then cut off, causing the power failure pin level to flip. The control module determines that the power supply has failed based on the hardware level change and drives the electronic expansion valve to complete the emergency closing protection against power failure. The relay synchronously cuts off the downstream load circuit. This can indicate the stability of the power supply under normal power supply conditions and realize power failure detection and emergency closing of the electronic expansion valve, avoiding equipment damage caused by accidental power failure. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0020] Figure 1 A schematic diagram of an electronic expansion valve control circuit provided in an embodiment of this application; Figure 2A schematic diagram of another electronic expansion valve control circuit provided in this application embodiment; Figure 3 A schematic diagram of another electronic expansion valve control circuit provided in the embodiments of this application; Figure 4 A schematic diagram of another electronic expansion valve control circuit provided in the embodiments of this application; Figure 5 A schematic diagram of another electronic expansion valve control circuit provided in the embodiments of this application; Figure 6 A schematic diagram of another electronic expansion valve control circuit provided in the embodiments of this application; Figure 7 A schematic diagram of another electronic expansion valve control circuit provided in the embodiments of this application; Figure 8 A schematic diagram of another electronic expansion valve control circuit provided in the embodiments of this application; Figure 9 A schematic diagram of another electronic expansion valve control circuit provided in the embodiments of this application; Figure 10 This is a schematic flowchart of an electronic expansion valve control method provided in an embodiment of this application; Figure 11 This is a schematic diagram of an electronic expansion valve control process provided in an embodiment of this application; Figure 12 This is a structural schematic diagram of a photovoltaic air conditioner provided in an embodiment of this application. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0023] This application provides an electronic expansion valve control circuit and control method, a photovoltaic air conditioner, and a storage medium. The electronic expansion valve control circuit includes: a power supply 10, a first resistor 20, an energy storage module 30, a relay 40, a second resistor 50, an optocoupler 60, a control module 70, and an electronic expansion valve 80. The first output terminal of the power supply 10 is connected to the first terminal of the energy storage module 30 via the first resistor 20. The first terminal of the energy storage module 30 is also connected to the normally closed terminal of the relay 40. The common terminal of the relay 40 is connected to both the first terminal of the control module 70 and the electronic expansion valve 80. The second output terminal of the power supply 10... The first terminal of the power supply 10 is connected to the first terminal of the control module 70 and the electronic expansion valve 80, respectively; the third output terminal of the power supply 10 is connected to the first terminal of the relay 40 coil and the collector of the optocoupler 60, respectively; the anode of the optocoupler 60 is connected to the power-down detection (POWERLOSS) pin of the control module 70; the second terminal of the energy storage module 30, the power supply 10, the second terminal of the relay 40 coil, the cathode and emitter of the optocoupler 60 are grounded; the control output terminal of the control module 70 is connected to the control terminal of the electronic expansion valve 80; the control module 70 is used to detect whether the power supply is down based on the power-down detection pin, and close the electronic expansion valve when the power supply is down.

[0024] like Figure 1 The diagram shown is a structural schematic of an electronic expansion valve control circuit provided in an embodiment of this application. This circuit can be applied to photovoltaic air conditioners. The electronic expansion valve 80 control circuit 10 includes: a power supply 10, a first resistor 20, an energy storage module 30, a relay 40, a second resistor 50, an optocoupler 60, a control module 70, and an electronic expansion valve 80. The first output terminal of the power supply 10 is connected to the first terminal of the energy storage module 30 through the first resistor 20. The first terminal of the energy storage module 30 is also connected to the normally closed terminal of the relay 40. The common terminal of the relay 40 is respectively connected to... The first terminal of the control module 70 is connected to the electronic expansion valve 80; the second output terminal of the power supply 10 is connected to the first terminal of the control module 70 and the electronic expansion valve 80 respectively; the third output terminal of the power supply 10 is connected to the first terminal of the relay coil 40 and the collector of the optocoupler 60 respectively; the anode of the optocoupler 60 is connected to the power-off detection pin of the control module 70; the second terminal of the energy storage module 30, the power supply 10, the second terminal of the relay coil 40, the cathode and emitter of the optocoupler 60 are grounded; the control output terminal of the control module 70 is connected to the control terminal of the electronic expansion valve 80.

[0025] For example, when power supply 10 is supplying power normally, the current output from the first output terminal of power supply 10 flows into the first terminal of energy storage module 30 after being current-limited by the first resistor 20 to charge energy storage module 30, and the second terminal of energy storage module 30 is grounded. The current output from the second output terminal of power supply 10 is connected to the first power supply terminal of control module 70 to provide power supply 10 for normal power supply state of control module 70; the other path is directly connected to the power supply terminal of electronic expansion valve 80, serving as power supply 10 for normal power supply state of valve body coil of electronic expansion valve 80.

[0026] The current output from the third output terminal of power supply 10 is connected to the first end of the coil of relay 40. The tail end of the relay 40 coil is grounded, and the coil is continuously energized. The internal mechanical structure of relay 40 is engaged, and the normally closed contact remains open, thus disconnecting the backup power supply path from energy storage module 30 to control module 70 and electronic expansion valve 80 via relay 40. This prevents energy storage module 30 from continuously discharging back to main power supply 10 under normal power supply conditions, which would cause losses. The second path is connected to the collector of the transistor in optocoupler 60. The anode of optocoupler 60 is driven by the POWERLOSS (power-down detection) pin of control module 70, and the cathode and emitter of optocoupler 60 are grounded. The internal LED of optocoupler 60 is energized and illuminates, and the phototransistor is grounded, causing the power-down detection pin of control module 70 to be at a low level, thereby controlling module 70. Based on the pin level characteristics, the main power supply 10 is determined to be supplying power normally. The second resistor 50 is connected in series in the power supply branch between the third output terminal of the power supply 10 and the optocoupler 60 (specifically, a light-emitting diode). As a current limiting protection element, it can limit the current flowing through the light-emitting diode of the optocoupler 60 when the power supply 10 is supplying power normally, avoiding the light-emitting diode from burning out due to overcurrent caused by fluctuations or overvoltage of the power supply bus voltage, and ensuring the long-term stable operation of the optocoupler 60. On the other hand, the second resistor 50 can match the conduction current parameters of the optocoupler to ensure that the optocoupler 60 can reliably conduct when the power supply 10 is supplying power normally, and output a stable low-level signal to the POWERLOSS pin of the control module 70. If the control module 70 determines that the POWERLOSS pin maintains a low level for a first preset duration, it determines that the power supply 10 is supplying power normally.

[0027] If power supply 10 loses power, all three output terminals of power supply 10 will have no output. The coil of relay 40 will lose power and the excitation magnetic force will disappear. The normally closed contacts inside will be reset and closed by mechanical spring force. The electrical energy stored at the first terminal of energy storage module 30 will be discharged outward. The current will flow out from the first terminal of energy storage module 30 and be divided into two outputs through the normally closed terminal of relay 40 and the closed common terminal: one output is connected to the power supply terminal of control module 70 to provide short-term emergency power to control module 70; the other output is used to power electronic expansion valve 80.

[0028] After the third output terminal loses power, the collector of optocoupler 60 has no input voltage, the internal diode of optocoupler 60 is de-energized, and the phototransistor changes from conducting to cut-off. The POWERLOSS pin of control module 70 loses its ground clamping position, and the pin level jumps from low level in the normal power supply state to high level. If control module 70 determines that the POWERLOSS pin will remain at a high level for the second preset time, it determines that the main power supply 10 has failed. With the support of the short-term discharge of energy storage module 30, control module 70 maintains operation by relying on emergency power supply and outputs a power failure drive signal from its own control output terminal to electronic expansion valve 80, driving electronic expansion valve 80 to perform a closing action, cutting off the refrigerant passage of the refrigeration pipeline, avoiding safety hazards such as refrigerant backflow in the pipeline, compressor liquid slugging, and system depressurization after power failure, and completing pipeline safety protection after the whole machine is powered off.

[0029] It should be noted that, in the embodiments of this application, the output voltages of the first output terminal, the second output terminal, and the third output terminal of the power supply 10 can be the same or different. For example, the voltage output by the first output terminal can be +13V, the voltage output by the second output terminal can be +12V, and the voltage output by the third output terminal can be +5V.

[0030] In this embodiment, during the normal power-on operation phase, the first output terminal of the power supply, through the first resistor, provides stable charging and energy storage to the energy storage module. The second and third output terminals continuously provide stable operating voltages to the control module, the electronic expansion valve drive circuit, and the relay coil. The optocoupler input terminal is energized and conducting, and the power failure detection pin remains at a low level. Based on this, the control module determines that the power supply is normal. When the main power supply experiences a sudden power failure, the second and third output terminals lose power. The diode on the second output side isolates the power supply port that has lost voltage. The energy storage module immediately releases its stored energy to supply power to the control module and the electronic expansion valve. The optocoupler then cuts off, causing the power failure pin level to flip. The control module determines that the power supply has failed based on the hardware level change and drives the electronic expansion valve to complete the emergency closing protection against power failure. The relay simultaneously cuts off the downstream load circuit. This can indicate the stability of the power supply under normal power supply conditions and realize power failure detection and emergency closure of the electronic expansion valve, avoiding equipment damage caused by unexpected power failures.

[0031] As an example, please see Figure 2 , Figure 2 This is a schematic diagram of another electronic expansion valve control circuit provided in an embodiment of this application. Figure 2As shown, in some embodiments, if the first connection line between the second output terminal of the power supply 10 and the control module 70 and the electronic expansion valve 80, and the second connection line between the energy storage module 30 and the control module 70 and the electronic expansion valve 80 are partially collinear, then the second output terminal of the power supply 10 is connected to the control module 70 and the electronic expansion valve 80 through the first diode, and the first end of the energy storage module 30 is connected to the control module 70 and the electronic expansion valve 80 through the second diode. The first diode connected in series at the second output terminal of power supply 10 serves as a one-way reverse current protection function. When power supply 10 is working normally, it is forward-biased, supplying current to the downstream relay 40, electronic expansion valve 80, and control circuit. When power supply 10 is powered off, it is reverse-biased when energy storage module 30 discharges, preventing energy from flowing back into the second output terminal of power supply 10 and damaging the internal components of power supply 10. The second diode at energy storage module 30 is responsible for working condition isolation and emergency power supply switching. When power supply 10 is supplying power normally, it is reverse-biased due to high potential clamping, isolating voltage changes in other lines from disturbing the charging link of energy storage module 30, ensuring that energy storage module 30 outputs power smoothly from the first output terminal of power supply 10 through the first resistor 20. When power supply 10 is powered off and the second and third output terminals lose voltage, the output voltage of energy storage module 30 drives the second diode to conduct in the forward direction, and energy storage module 30 can then supply power to the downstream load for a short time through the conducting diode, ensuring that control module 70 completes the power failure signal acquisition and the power failure reset action of electronic expansion valve 80.

[0032] In some embodiments, the energy storage module 30 includes at least one RC energy storage unit, each RC energy storage unit including a set of capacitors and resistors connected in parallel.

[0033] As an example, please see Figure 3 , Figure 3 This is a schematic diagram of another electronic expansion valve control circuit provided in an embodiment of this application. Figure 3As shown, in this embodiment, the energy storage module 30 is composed of three sets of parallel RC energy storage units arranged side by side. The capacitors and resistors within each RC energy storage unit are connected in parallel. The three sets of RC units are then connected in parallel to the circuit. During normal power supply from the power supply 10, the capacitors of each RC unit are simultaneously charged. The equalizing resistor can balance the leakage voltage of the capacitors in the same branch, suppress potential overvoltage breakdown of the energy storage capacitors, and simultaneously, based on the voltage regulation characteristics of the parallel RC circuit, smooth out instantaneous peak impacts on the bus, absorb high-frequency noise interference, optimize the charging stability of the energy storage module 30, and prevent... To prevent the internal resistance of the energy storage capacitor from changing after long-term use, which could cause the voltage drop across the capacitor to exceed the rated voltage and damage the capacitor; when the power supply 10 fails, each energy storage capacitor in the energy storage module 30 discharges synchronously in reverse parallel to the outside, relying on the large capacity energy storage advantage brought by the parallel connection of multiple capacitors to continuously output electrical energy. The parallel resistance of each branch limits the peak discharge current of the capacitor to avoid the large current impact on the downstream controlled load during discharge, and balances the discharge rate of each group of capacitors through the RC discharge path to prevent overload of other devices caused by premature discharge of some capacitors.

[0034] It should be noted that, in the embodiments of this application, the energy storage module 30 may include at least one set of parallel RC energy storage units. Figure 3 Taking a three-unit parallel RC energy storage system as an example, the resistors and capacitors in the RC charging circuit can be adjusted according to the actual situation.

[0035] In this embodiment, the overall energy storage capacity can be increased and the backup power supply time after power failure can be extended by connecting multiple parallel RC energy storage modules 30. Furthermore, by configuring parallel resistors in each circuit, multiple protections such as voltage equalization of individual capacitors, current limiting, and protection against overcharging and over-discharging can be achieved to adapt to emergency drive scenarios of circuits that require short-term backup power supply after power failure.

[0036] In one implementation, the control module 70 further includes a voltage sampling pin, and the first end of the energy storage module 30 is also connected to the voltage sampling pin of the control module 70.

[0037] As an example, please see Figure 4 , Figure 4 This is a schematic diagram of another electronic expansion valve control circuit provided in an embodiment of this application. Figure 4 As shown, the control module 70 is equipped with an ADC_V (voltage sampling) pin. The first terminal of the energy storage module 30 is connected to this ADC_V pin, so the control module 70 can obtain the sampled voltage value of the energy storage module 30 through the ADC_V pin. Based on the sampled voltage value, the control module 70 can monitor the stored power and charging status of the energy storage module 30, thereby realizing real-time monitoring of the energy storage capacity. For example, the sampled voltage value can be compared with a preset voltage threshold. If the sampled voltage value is greater than or equal to the voltage threshold, the energy storage module 30 can be determined to be normal.

[0038] In this embodiment, voltage sampling can be used to determine whether the energy storage status of the energy storage unit meets the standard. If the energy storage is depleted or malfunctioning, when the power supply fails, there will be insufficient power to drive the control module to perform the action of the electronic expansion valve. This can easily lead to power failure during valve closure and failure of the valve to close completely. If the electronic expansion valve remains open after the refrigeration system is powered off, it will cause abnormal refrigerant backflow, system pipeline pressure imbalance, and damage to the matching compressor, among other safety hazards. Therefore, this application can, under the premise that the energy storage unit is functioning normally, drive the control module to execute control commands to close the electronic expansion valve based on the power output of the energy storage unit, thereby achieving safe closure of the electronic expansion valve under power failure conditions.

[0039] In some embodiments, a voltage divider filter module is also provided between the first end of the energy storage module 30 and the voltage sampling pin of the control module 70.

[0040] In one optional implementation, the voltage divider filter module includes a third resistor, a fourth resistor, a fifth resistor, and a filter capacitor; wherein, the first terminal of the energy storage module 30 is connected to the first terminal of the third resistor, the second terminal of the third resistor is grounded after passing through the fourth resistor, the second terminal of the third resistor is also connected to the first terminal of the fifth resistor, the fifth terminal of the fourth resistor is connected to the control module 70, and the second terminal of the fourth resistor is grounded through the filter capacitor.

[0041] As an example, please see Figure 5 , Figure 5 This is a schematic diagram of another electronic expansion valve control circuit provided in an embodiment of this application. Figure 5 As shown, a voltage divider and filter module can be set between the first terminal of the energy storage module 30 and the voltage sampling pin of the control module 70. On the one hand, the output voltage of the energy storage module 30 can be divided by resistance to reduce the voltage output of the energy storage module that exceeds the withstand voltage range of the voltage sampling pin of the control module 70 to the rated voltage of the sampling port, so as to avoid the high voltage of the energy storage directly entering the pin and causing the port to be damaged by overvoltage.

[0042] In some embodiments, if a voltage divider filter module is provided between the first terminal of the energy storage module 30 and the voltage sampling pin of the control module 70, then the control module 70 can calculate the voltage of the energy storage module 30 based on the voltage value measured by the voltage sampling pin, which can be specifically expressed as:

[0043] in, The voltage value is measured at the ADC pin. This is the resistance value of the third resistor. This is the resistance value of the fourth resistor.

[0044] In one alternative implementation, there is at least one electronic expansion valve 80, and the control module 70 includes a main control unit (e.g., MCU (Microcontroller Unit)) and at least one drive unit, each drive unit corresponding to one electronic expansion valve 80, and the main control unit controls the corresponding electromagnetic expansion valve through each drive unit.

[0045] As an example, please see Figure 6 , Figure 6 This is a schematic diagram of another electronic expansion valve control circuit provided in the embodiment of the fundamental application. For example... Figure 6 As shown, the control module 70 may include a main control unit 71 and a drive unit 72. Each drive unit 72 is connected to an electronic expansion valve 80. The main control unit 71 can control the corresponding electromagnetic expansion valve through each drive unit.

[0046] It should be noted that the number of drive units 72 can be configured based on the number of electronic expansion valves 80, and each drive unit 72 can correspond to at least one electronic expansion valve 80.

[0047] In this embodiment, a control architecture combining a main control unit and an independent drive unit can be adopted to achieve control isolation of different electronic expansion valves. The failure of a single drive unit or electronic expansion valve will not affect the control of the remaining electronic expansion valves. Furthermore, the drive unit performs specific control of the electronic expansion valves, which facilitates the expansion of the number of controlled electronic expansion valves and the precise regulation of each electronic expansion valve.

[0048] In one implementation, the power supply 10 includes a first transformer, a second transformer, and a third transformer. The first transformer, the second transformer, and the third transformer obtain electrical energy from the power grid and output it. The output terminal of the first transformer is the first output terminal, the output terminal of the second transformer is the second output terminal, and the output terminal of the third transformer is the third output terminal.

[0049] As an example, please see Figure 7 , Figure 7 This is a schematic diagram of another electronic expansion valve control circuit provided in an embodiment of this application. Figure 7 As shown, multiple independent transformers can be used as power sources 10. The three transformers draw power from the power grid and output different voltages after independent transformation. The output terminal of the first transformer 11 corresponds to the aforementioned first output terminal, the output terminal of the second transformer 12 corresponds to the aforementioned second output terminal, and the output terminal of the third transformer 13 corresponds to the aforementioned third output terminal.

[0050] In the embodiments of this application, the aforementioned power grid can be a municipal power grid or a new energy power grid (e.g., a photovoltaic power grid). A rectifier bridge can be installed between the power grid and the transformer.

[0051] In this embodiment, by adopting a multi-transformer independent voltage transformation design, the voltage can be adjusted separately for the different rated voltage requirements of the energy storage charging, main control and electronic expansion valve 80 power supply, relay 40 and optocoupler 60 detection circuit. Each power supply branch is isolated from each other, and the failure of a single transformer will not interfere with the normal power supply of the other circuits. This effectively suppresses voltage ripple and electrical interference between different branches and improves circuit stability.

[0052] As an example, please see Figure 8 , Figure 8 This is a schematic diagram of another electronic expansion valve control circuit provided in the embodiments of this application.

[0053] As an example, please see Figure 9 , Figure 9 This is a schematic diagram of another electronic expansion valve control circuit provided in an embodiment of this application. Figure 9 As shown, power supplies B and A are supplied by a common mains power source. After rectification by a rectifier bridge, they are converted into different voltages by high-frequency transformers B and A, respectively. Under normal operating conditions, the two power supplies are isolated from each other.

[0054] High-frequency transformer B, diode D4, and capacitor C4 constitute power supply B. The output of power supply B, +13V_B, charges the RC charging circuit. Resistors R(n+1), R(n+2), and R(n+3) constitute resistor R, and capacitors C4, C5, and Cn constitute energy storage capacitor C. The resistors and capacitors in the RC charging circuit can be adjusted according to actual conditions. Theoretically, it takes 5 × R × C to fully charge the voltage. Resistors R4, R5, and Rn form voltage-equalizing resistors, the number of which matches the number of energy storage capacitors. One voltage-equalizing resistor is connected in parallel with each energy storage capacitor. This prevents the voltage drop across the capacitor from exceeding the rated voltage due to changes in internal resistance after long-term use, which could damage the capacitor. After power-on, the energy storage capacitor will slowly charge to V_C, and then the voltage across the energy storage capacitor will remain at V_C. Resistors R1 and R2 form a voltage divider. The voltage obtained from the voltage sampling pin is V_C*R2 / (R1+R2). This voltage is lower than the voltage that the sampling port of the main chip U1 can withstand. Resistor R3 and capacitor C1 form an RC filter circuit to filter out interference noise, making the sampled voltage smoother and avoiding misjudgment. The sampled voltage is processed by real-time logic judgment to ensure that the backup voltage is normal. Once the voltage is abnormal, a fault is reported.

[0055] A high-frequency transformer A, diode D3, and capacitor C3, along with diode D2 and capacitor C2, constitute power supply A, outputting +5V_A and +12V_A respectively. The +5V_A supplies power to the coil of relay K1. Upon power-up, the coil of relay K1 is energized, causing the contacts of relay K1 to disconnect from the idle terminal, thus disconnecting the V_C and +12V_A lines. At this moment, the +13V_B power supply charges the RC charging circuit, but there is no discharging circuit. Simultaneously, diode D5 isolates the V_C and +12V_A lines, ensuring that the energy storage capacitor C only functions on either the V_C or +12V_A line. The +12V_A, after passing through diode D1, supplies power to the electronic expansion valve and its driver chips (equivalent to the aforementioned driver units) U2 and U3. Simultaneously, after power conversion, it supplies power to the main chip, enabling the control logic to operate normally.

[0056] When the mains power supply fails, both power sources B and A become ineffective, meaning the power to the coil of relay K1 also fails. The contacts of relay K1 then switch to the active side, connecting the V_C and +12V_A networks. Since the energy storage capacitor was already fully charged, V_C temporarily replaces +12V_A to provide power after the mains power failure. The main chip (equivalent to the aforementioned main control unit) U1 controls the drive chip U2, which in turn closes the electronic expansion valve. This prevents refrigerant leakage into the piping and creates conditions for refrigerant recovery to the compressor.

[0057] Whether the mains power is down can be determined by the level change of the POWERLESS pin. U3 is an optocoupler that isolates the two power supplies. Resistor R6 is a current-limiting resistor, and R7 is a pull-up resistor. When POWERLESS is low, it is determined that the mains power supply is normal. Conversely, it is determined that the mains power is down.

[0058] As an example, please see Figure 10 , Figure 10 This is a schematic flowchart of an electronic expansion valve control method provided in an embodiment of this application. This method can be applied to the electronic expansion valve control circuit provided in any embodiment of this application. Figure 10 As shown, the method may include, but is not limited to, the following steps: Step S1001: Obtain the level change of the power failure detection pin, and detect whether the power supply is cut off based on the level change.

[0059] For example, when the power supply is working normally, the voltage output by the power supply turns on the optocoupler, which pulls the power failure detection pin of the control module to a low level, and the control module determines that the power supply is normal. When the power supply fails, the optocoupler turns off, and the power failure detection pin is pulled high, so the control module can identify the power failure state by the change in the pin level.

[0060] Step S1002: Determine that the power supply is off, and close the electronic expansion valve while the energy storage module is supplying power.

[0061] In some embodiments, the above method may further include: acquiring the sampled voltage value of the voltage sampling pin, and detecting whether the energy storage module is storing energy normally based on the sampled voltage value.

[0062] For example, the control module collects the voltage signal of the energy storage module in real time through the voltage sampling pin and continuously monitors the change of the second level of the sampling pin. The MCU compares the actual voltage value corresponding to the level with the preset normal voltage threshold range. If the level rises steadily during charging and falls slowly during power-off discharge, it is determined that the energy storage charging and discharging performance is normal. If the level drops abruptly and the voltage cannot rise gradually with charging, the energy storage module is identified as abnormally malfunctioning.

[0063] Optionally, the above-mentioned determination of power failure and closing the electronic expansion valve under the power supply of the energy storage module includes: determining whether the power failure occurs and whether the energy storage module is storing energy normally, and closing the electronic expansion valve under the power supply of the energy storage module.

[0064] In one alternative implementation, after the power supply is turned on, the above-mentioned steps of obtaining the sampling voltage value of the voltage sampling pin and detecting whether the energy storage module is storing energy normally can be started after a preset time.

[0065] The aforementioned pre-defined market can be determined by the energy stored in the RC energy storage device.

[0066] It should be noted that after a power outage, the control module and electronic expansion valve lose their original operating power and can only rely on the energy storage unit for emergency power. Therefore, it is necessary to first use ADC_V voltage sampling to determine whether the energy storage status of the energy storage unit meets the standard. If the energy storage is depleted or malfunctioning, there will be insufficient power for the control module to execute the closing action of the electronic expansion valve, which can easily lead to power failure during valve closing or incomplete valve closure. If the electronic expansion valve remains open after a power outage in the refrigeration system, it will cause abnormal refrigerant backflow, system pipeline pressure imbalance, and damage to the matching compressor, among other safety hazards. Therefore, only when it is confirmed that the energy storage unit is storing energy normally, and the energy storage unit outputs power to drive the control module to execute control commands and reliably close the electronic expansion valve, can the safe interlocking of the refrigeration pipeline be achieved under power failure conditions, thus avoiding the risk of abnormal damage to the system.

[0067] As an example, please see Figure 11 , Figure 11 This is a schematic diagram of an electronic expansion valve control process provided in an embodiment of this application. This control process can be applied to, for example... Figure 11 The electronic expansion valve control circuit shown is illustrated. Figure 11As shown, after the power supply is turned on, it charges the energy storage capacitor on one hand, and on the other hand, the main control chip controls the opening of the electronic expansion valve according to the preset normal control logic. Only when the energy storage capacitor is fully charged and the mains power is cut off will the backup power supply be triggered. At this time, the main control chip detects the mains power failure signal and then uses the backup power to execute the valve closing logic to prevent refrigerant from leaking into the pipeline and to create conditions for the refrigerant to flow back to the compressor. Specifically, the I / O of the main control unit is initialized first, configuring the ADC_V pin as an input port ADC function, configuring the EXVa_1, EXVa_2, EXVa_3, EXVa_4, EXVb_1, EXVb_2, EXVb_3, EXVb_4 pins as output ports, and configuring the POWERLOSS pin as an input port.

[0068] The voltage of the ADC_V line is then continuously sampled, and the voltage value V_C is calculated. Simultaneously, the power-on time is recorded, and it is determined whether the power-on timer has reached 5RC. If not, the timer continues until 5RC is reached. If the timer reaches 5RC, the voltage V_C is checked within a first preset time period to see if it has reached a preset voltage value. If not, an abnormality in the backup voltage V_C is reported, indicating an abnormal energy storage status of the energy storage unit. If the voltage V_C reaches the set value, the backup voltage V_C is marked as being within the normal range, indicating that the energy storage status of the energy storage unit is normal.

[0069] Simultaneously, it continuously checks whether the POWERLESS potential is low. If the POWERLESS potential is low, it indicates that the mains power supply is normal. Then, the MCU controls the opening of the electronic expansion valve according to normal logic through the EXVa_1, EXVa_2, EXVa_3, EXVa_4, EXVb_1, EXVb_2, EXVb_3, and EXVb_4 lines.

[0070] If the POWERLESS potential is not low, it is determined that the mains power has failed, and the backup voltage V_C is checked again to see if it is within the normal range. If it is, powered by the energy storage capacitor, the MCU controls the driver chip to close the electronic expansion valve through the EXVa_1, EXVa_2, EXVa_3, EXVa_4, EXVb_1, EXVb_2, EXVb_3, and EXVb_4 circuits. If not, an abnormality in the backup voltage V_C is reported.

[0071] Corresponding to the above method embodiments, this application also provides a photovoltaic air conditioner, such as... Figure 12 As shown, it includes a processor 1201, a communication interface 1202, a memory 1203, and a communication bus 1204. The processor 1201, the communication interface 1202, and the memory 1203 communicate with each other through the communication bus 1204. Memory 1203 is used to store computer programs; When processor 1201 executes the program stored in memory 1203, it performs the following steps: The system acquires the voltage level change of the power failure detection pin and detects whether the power supply is interrupted based on the voltage level change; if the power supply is interrupted, the electronic expansion valve is closed under the power supply of the energy storage module.

[0072] In an alternative implementation, the processor 1201 is further configured to perform the following steps: acquire the sampled voltage value of the voltage sampling pin, and detect whether the energy storage module is storing energy normally based on the sampled voltage value.

[0073] Optionally, the processor 1201 is also configured to perform the following steps: determine whether the power supply is lost and whether the energy storage module is storing energy normally, and close the electronic expansion valve when the energy storage module is powered.

[0074] The communication bus mentioned in the photovoltaic air conditioner diagram can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. This communication bus can be divided into address bus, data bus, and control bus. For ease of illustration, only one thick line is used in the diagram, but this does not indicate that there is only one bus or one type of bus.

[0075] The communication interface is used for communication between the aforementioned photovoltaic air conditioner and other devices.

[0076] The memory may include random access memory (RAM) or non-volatile memory, such as at least one disk storage device. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor.

[0077] The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0078] In another embodiment provided in this application, a storage medium is also provided, which stores instructions that, when run on a computer, cause the computer to execute the control method of any of the charging circuits described in the above embodiments.

[0079] In another embodiment provided in this application, a computer program product containing instructions is also provided, which, when run on a computer, causes the computer to execute the control method of the charging circuit described in any of the above embodiments.

[0080] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a storage medium or transmitted from one storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid state disk (SSD)).

[0081] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0082] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0083] The above description is merely a preferred embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application are included within the scope of protection of this application.

Claims

1. An electronic expansion valve control circuit, characterized in that, include: The system includes a power supply, a first resistor, an energy storage module, a relay, a second resistor, an optocoupler, and a control module; among which, The first output terminal of the power supply is connected to the first terminal of the energy storage module through a first resistor; The first end of the energy storage module is also connected to the normally closed end of the relay; The common terminal of the relay is connected to the first terminal of the control module and the electronic expansion valve, respectively. The second output terminal of the power supply is connected to the first terminal of the control module and the electronic expansion valve, respectively. The third output terminal of the power supply is connected to the first terminal of the relay coil and the collector of the optocoupler, respectively. The second resistor is connected in series in the power supply branch of the third output terminal of the power supply and the optocoupler. The anode of the optocoupler is connected to the power failure detection pin of the control module. The control output terminal of the control module is connected to the control terminal of the electronic expansion valve. The control module is used to detect whether the power supply is down based on the power failure detection pin, and to close the electronic expansion valve when it is determined that the power supply is down.

2. The control circuit according to claim 1, characterized in that, The energy storage module includes at least one RC energy storage unit, and each RC energy storage unit includes a set of capacitors and resistors connected in parallel.

3. The control circuit according to claim 1, characterized in that, The control module includes a voltage sampling pin, and the first end of the energy storage module is also connected to the voltage sampling pin of the control module.

4. The control circuit according to claim 3, characterized in that, A voltage divider filter module is also provided between the first end of the energy storage module and the current sampling pin of the control module.

5. The control circuit according to claim 4, characterized in that, The voltage divider filter module includes a third resistor, a fourth resistor, a fifth resistor, and a filter capacitor; wherein, The first end of the energy storage module is connected to the first end of the third resistor. The second end of the third resistor is grounded after passing through the fourth resistor. The second end of the third resistor is also connected to the first end of the fifth resistor. The fifth end of the fourth resistor is connected to the control module. The second end of the fourth resistor is grounded through the filter capacitor.

6. The control circuit according to claim 1, characterized in that, The electronic expansion valve is at least one, and the control module includes a main control unit and at least one drive unit. Each drive unit corresponds to one electronic expansion valve, and the main control unit controls the corresponding electromagnetic expansion valve through each drive unit.

7. The control circuit according to claim 1, characterized in that, The power source includes a first transformer, a second transformer, and a third transformer. The first transformer, the second transformer, and the third transformer obtain electrical energy from the power grid and output it. The output terminal of the first transformer is the first output terminal, the output terminal of the second transformer is the second output terminal, and the output terminal of the third transformer is the third output terminal.

8. A method for switching backup power to close an electronic expansion valve upon power failure, the method being applied to a control module in a circuit as described in any one of claims 1-7, the method comprising: Acquire the level change of the power failure detection pin, and detect whether the power supply is cut off based on the level change; Once the power supply is confirmed to be down, the electronic expansion valve is closed while the energy storage module is providing power.

9. A photovoltaic air conditioner, characterized in that, It includes a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus; Memory, used to store computer programs; A processor, when executing a program stored in memory, implements the method of claim 8.

10. A storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the method as described in claim 8.

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